To add to what Georgehifi said: About 15 years ago R2R DACs were indeed better sounding than early Delta Sigma DACs. However early Delta Sigma issues (glare) have been resolved and their performance currently far exceeds R2R.
The most lauded and celebrated and lusted after dacs in current cutting edge technology.... are all R2R discrete dacs.
going back in time and buying a 20-24 bit R2R dac unit and upgrading it, and using it for redbook 16/44 playback, will far exceed what any delta-sigma dac can achieve.
The manufactures of the units that use delta-sigma dacs (99.9% of all audio dacs available these days) would gladly use R2R dacs in their units, but those R2R dacs are simply not available at any price.
They are simply too expensive to make via the wafer process for IC manufacturing, in modern times.
You can’t put a $100 chip (when bought in thousand lots) in a $200 or even $800 dac unit. It has to be a $3-8 delta-sigma single-bit dac chip. Which they all are.
In the world of digital....It is a elephantine, 800 pound gorilla in the room, "bull in a china shop" "emperor’s clothes" issue in audio, where we all had to take a DOWNGRADE in musical quality when the industry was forced to call it an UPGRADE (measures well, looks great on paper!), as no alternative existed to go forward and upward with.
The whole thing went Orwellian doublespeak and pear-shaped, due to the introduction of more than 16 bits of resolution. When we went to 20 bits, we could make a $10 (thousand lots) chip, and when we went to 24/96, we could do a $50 (thousand lots) DAC chip, but when we went beyond that..to 24/192 and then 32 bit..we could no longer produce a R2R dac on a chip.
If even possible, they might be some astronomical cost per individual item. Suffice it to say... it is not really possible to do a 32 bit R2R DAC wafer based IC chip... it is a theoretical projection. It simply cannot be done. Price is: infinity. Simply not gonna ever happen.
So we were stuck trying to jerry-rig a delta sigma bit chip to being good. That mess is still being fixed, but the industry cannot wait, so it used and uses..... inferior sounding chips to get to these high sample rates. According to the principle on how a delta-sigma dac works, the problem will never be fixed.
the entire digital audio world took one in the butt and was forced to cover it up in order to stay in business and move onward. Very little was spoken about this when it went down and now that the moment is in the past, the more finalized shape of it ...is saying exactly what I’m saying here.
Obviously, no one wants to say much about it. these things happen. Just like digital originally was a step backward from the best in analog..and it slowly evolved, even digital in it’s own market and design issues, etc...suffered the same fate at a point in it’s evolution. One that is still affecting it today.
The alternative... is a 24 to 32 bit discrete ladder/R2R dac, coming in at about $15k US for a stereo unit as the baseline cost in the market for one of them. Then the price goes up from there.
They (dac chip companies) are coming up with different schemes to improve the delta-sigma base design parameters at the design and execution level (wafer design compatible), and have issued such, but we are still not back to the quality level available from the $50 chips, the 24/96 ladder/R2R dacs that were available in the early-mid 2000's.
The problem for the high end audiophile market is that price drives development as the prime motivator and market force.
Audiophile sound quality aspects are 2nd, 3rd, or 4th down on the list.The next limitation point is the one mentioned, the wafer design/build limits. That's the part that is really getting in the way. Costs vs quality vs technology available. Same questions as ever.
